Various motors have been used during the last century in order to convert electric energy into mechanical energy. Some motors run on DC currents, others are to operate on AC currents, whereas others may run on both the DC and AC currents, where examples of such motors may include, but not be limited to, DC motors including movable rotors (which are generally electromagnets) and stationary stators (which are permanent magnets), universal motors with rotors (which are electromagnets) and stators (which are electromagnets), single-phase or three-phase synchronous AC motors with rotors (which are permanent magnets) and stators (which are electromagnets), single-phase or three-phase induction AC motors including rotors (which are neither permanent magnets, nor electromagnets, but conductive metals) and stators (which are electromagnets), stepping motors having rotors (which are permanent magnets) and stators (which are electromagnets), linear motors having rotors (which are permanent magnets or electromagnets) and stators (which are electromagnets), advanced AC motors based upon inverter or converter technology such as, e.g., switch reluctance motors and brushless DC motor, and other motors such as, e.g., torque motors, servo motors, coreless DC motors, printed circuit motors, and the like.
Although such motors may generate desired torque, they invariably irradiate a massive amount of undesirable or harmful electromagnetic waves (to be abbreviated as “harmful EM waves” or simply “harmful waves” hereinafter). For example, an electromagnet-type rotor irradiates the harmful waves as the AC current flows therein. Even when such a rotor runs on the DC current, rotation of the rotor inevitably bends and twists static magnetic fluxes, thereby irradiating the harmful EM waves of which characteristics may be determined by a speed of rotation. Similarly, an electromagnet-type stator also emits the harmful waves as the AC current flows therein. Even when the stator is an electromagnet running on the DC current or when the stator is a permanent magnet, the harmful waves irradiated by the stator tend to propagate to the stator which then disperse such waves away therefrom. In short, every motor which invariably includes at least one electromagnet irradiates the harmful EM waves due to either the AC current flowing therein or the movement of the rotor.
Numerous attempts have been made to reduce the harmful EM waves irradiated from different portions of conventional motors. For example, electrically conductive articles have been incorporated into various locations in and around the motors as have been exemplified in U.S. Pat. No. 6,888,062 B1 to S. Erikson, U.S. Pat. No. 6,858,955 B2 to J. C. S. Lau, U.S. Pat. No. 6,530,757 B1 to W. Soyer et al., U.S. Pat. No. 6,528,915 B1 to F. Moskob, U.S. Pat. Nos. 6,522,516 B2 and 6,509,807 B1 to A. Anthony et al., U.S. Pat. No. 6,321,563 B1 to H. Ikeda, U.S. Pat. No. 6,302,747 B1 to Bui, U.S. Pat. No. 6,129,948 to H. Plummer et al., U.S. Pat. No. 6,129,074 to K. Frank, U.S. Pat. No. 6,099,757 to V. C. KulKarni, U.S. Pat. No. 6,078,117 to R. L. Perrin et al., U.S. Pat. No. 5,973,906 to R. A. Stevenson et al., U.S. Pat. No. 5,646,498 to T. A. Lipo et al., U.S. Pat. No. 5,313,126 to J. A. Forsythe et al., U.S. Pat. No. 5,038,088 to G. E. Arends et al., U.S. Pat. No. 4,753,169 to M. W. Shores, and the like.
In other attempts, varistors, resistors, capacitors, and choke circuits with such elements have also been incorporated in or around the motors individually or as printed circuit boards as exemplified in U.S. Pat. No. 7,038,337 B2 to K. S. Thomson, U.S. Pat. No. 6,992,414 B2 to K. S. Thomson et al., U.S. Pat. Nos. 6,603,646 B2 and 6,594,128 B2 to A. A. Anthony, U.S. Pat. No. 6,583,682 B1 to A. Dubhashi et al., U.S. Pat. No. 6,580,931 B1 to S. Shiotsu et al., U.S. Pat. Nos. 6,580,595 B2 and 6,549,389 B2 to A. A. Anthony et al., U.S. Pat. No. 6,529,103 B1 to R. L. Brendl et al., U.S. Pat. No. 6,498,710 B1 to A. A. Anthony, U.S. Pat. No. 6,469,595 B2 to A. A. Anthony et al., U.S. Pat. No. 6,400,058 B1 to B. Liau, U.S. Pat. Nos. 6,388,856 B1, 6,373,673 B1, 6,331,926 B1, 6,282,074 B1, and 6,097,581 to A. Anthony, U.S. Pat. No. 6,008,980 to R. A. Stevenson et al., U.S. Pat. No. 5,995,347 to J. P. Rudd, U.S. Pat. No. 5,905,627 to R. Brendl et al., U.S. Pat. No. 5,880,937 to K. Schadhauser et al., U.S. Pat. No. 5,661,390 to T. A. Lipo et al., U.S. Pat. No. 5,396,214 to A. K. Kumar, U.S. Pat. No. 5,208,499 to H. C. Barber, U.S. Pat. No. 4,814,687 to C. S. Walker, and the like.
Others have attempted to reduce arcing and radiation of the harmful EM waves as exemplified in U.S. Pat. Nos. 7,051,420 B2, 7,000,307 B2, 6,930,429 B2, and 6,566,782 B1 to R. H. Wang, U.S. Pat. No. 6,400,058 B1 to B. L. Liau, U.S. Pat. No. 5,694,798 to P. Nunez et al., U.S. Pat. No. 5,208,499 to H. C. Barber et al., U.S. Pat. No. 4,329,610 to H. Klein, and U.S. 2006/0082244 A1 to T. Kuechen et al. In other attempts, voltages and/or currents have been regulated by various means as also exemplified in U.S. Pat. No. 7,053,571 B1 to P. J. VanDrunen et al., U.S. Pat. No. 7,042,198 B2 to N. Mutoh, U.S. Pat. No. 6,975,459 B2 to Y. Kokami et al., U.S. Pat. No. 6,943,510 B2 to B. Gorti, U.S. Pat. No. 6,903,894 B2 to Y. Kokami et al., U.S. Pat. No. 6,819,076 B2 to T. Takahashi, U.S. Pat. No. 6,150,789 to R. Pulford, Jr., U.S. Pat. No. 6,049,184 to D. Uggla, U.S. Pat. No. 6,008,560 to R. Becerra, U.S. Pat. Nos. 5,859,511 and 5,668,449 to F. Carobolante, U.S. Pat. No. 5,838,515 to S. Mortazavi et al., U.S. Pat. No. 4,728,866 to D. Capewell et al., U.S. Pat. No. 4,504,779 to D. J. Haman, and the like. In other attempts, various provisions have been made to motor and/or pump assemblies as exemplified in U.S. Pat. No. 6,580,610 B2 to T. L. Morris et al., U.S. Pat. No. 6,507,492 B2 to T. L. Morris et al., U.S. Pat. No. 6,232,684 B1 to R. H. Haag et al., U.S. Pat. No. 6,107,716 to D. M. Penketh, U.S. Pat. No. 4,829,207 to J. J. Hovorka, and the like.
In addition to the foregoing, other minor implementations or modifications have been proposed to reduce the irradiation of the harmful waves examples of which may include U.S. Pat. No. 6,765,711 B2 to Y. H. Min et al., U.S. Pat. No. 6,753,629 B2 to Doi et al., U.S. Pat. No. 6,606,011 B2 to A. Anthony et al., U.S. Pat. No. 6,501,609 B2 to T. Saito et al., U.S. Pat. No. 6,021,015 to E. Jeffrey et al., U.S. Pat. No. 5,879,785 to H. J. Shin, U.S. Pat. No. 5,780,952 to Lau, U.S. Pat. No. 5,757,628 to Kamata, U.S. Pat. No. 5,723,924 to Blanchet, U.S. Pat. No. 5,718,259 to Miyake et al., U.S. Pat. No. 5,697,769 to Kobman et al., U.S. Pat. No. 5,610,467 to K. S. Shiah et al., U.S. Pat. No. 5,605,129 to Strombeck et al., U.S. Pat. No. 5,586,613 to M. Ehsani, U.S. Pat. No. 5,415,906 to T. Miyakawa et al., U.S. Pat. No. 5,409,399 to F. L. Geoghegan et al., U.S. Pat. No. 5,360,353 to Kinoshita, U.S. Pat. No. 5,345,124 to Lang, U.S. Pat. No. 5,329,788 to J. L. Caillat et al., U.S. Pat. No. 5,313,126 to J. Forsythe et al., U.S. Pat. No. 5,311,398 to Schirmer et al., U.S. Pat. No. 5,298,903 to Janos, U.S. Pat. No. 5,287,028 to Suzuki et al., U.S. Pat. No. 5,281,876 to Sato, U.S. Pat. No. 5,196,750 to G. Strobl, U.S. Pat. No. 5,196,747 to W. Kress et al., U.S. Pat. No. 5,072,358 to Lankford, U.S. Pat. No. 4,933,586 to Gotou, U.S. Pat. No. 4,895,536 to Ginferich et al., U.S. Pat. No. 4,746,829 to Strobl, U.S. Pat. No. 4,728,835 to R. F. Baines, U.S. Pat. No. 4,727,274 to Adam et al., U.S. Pat. No. 4,699,466 to Brandstetter et al., U.S. Pat. No. 4,600,971 to Rose et al., U.S. Pat. No. 4,596,519 to C. Tuckey, U.S. Pat. No. 4,494,024 to Braun, U.S. Pat. No. 4,465,331 to 1. Masuda et al., U.S. Pat. No. 4,417,388 to Major, U.S. Pat. No. 4,384,223 to Zelt, U.S. Pat. No. 4,329,610 to Klein, U.S. Pat. No. 4,329,605 to Angi et al., U.S. Pat. No. 4,292,559 to Auinger et al., U.S. Pat. No. 4,157,483 to C. H. Frimley, U.S. Pat. No. 3,924,147 to Tarnow et al., U.S. Pat. No. 3,913,346 to H. W. Moody, Jr. et al., U.S. Pat. No. 3,631,278 to Snively, U.S. Pat. No. 2,921,207 to Fletcher, U.S. Pat. No. 2,103,166 to Morrill, U.S. Pat. No. 841,545 to Latour, and the like.
Although all of the above conventional techniques are at best marginally effective in shielding electric components (to be abbreviated as “electric waves” hereinafter) of such harmful waves, they do not constitute any defense at all in shielding magnetic components (to be abbreviated as “magnetic waves” hereinafter) of the harmful waves, for the magnetic waves of the harmful waves propagate through the conductive electric shields as if there exists nothing inbetween. The magnetic waves of the harmful waves may only be effectively shielded by either of two following mechanisms such as, e.g., by absorbing, rerouting, and optionally terminating such magnetic waves in a magnetic pole or by emitting counter electromagnetic waves (to be abbreviated as “counter EM waves” or simply “counter waves” hereinafter) and canceling a desired portion of the magnetic waves by the counter waves.
Therefor, there is a need for an electric motor system which irradiates only a minimal amount of the harmful waves. There also is a need for various mechanisms for minimizing such irradiation of the harmful waves by the electric motor system. Such mechanisms are preferably inplementable into various electric motor systems without requiring severe changes in its design and/or size. In addition, such mechanisms are preferably at least benign to normal operation of such systems without causing any adverse effects on their capability of generating electromotive force and/or torque. There also is a need for various counter units which may be incorporated into various locations of the systems and minimize such irradiation through various mechanisms.